1. Field of the Invention
The present invention relates to an electromagnetic wave measuring apparatus. More particularly, the present invention relates to an electromagnetic wave measuring apparatus which measures an electromagnetic wave radiated from an antenna to be measured by detecting it by means of a plurality of probe antennas.
2. Related Art
A conventional electromagnetic wave measuring apparatus measures an electromagnetic wave radiated from an antenna to be measured on a partial sphere by scanning a large measuring antenna such as a dipole antenna, on a circular arc the center of which is positioned at the antenna to be measured or rotating the antenna to be measured at the center of the aforementioned circular arc.
A high-speed diagnostic testing of a microwave antenna by means of a probe array in accordance with an advanced modulated scattering technique (A-MST) is disclosed in “Applications of A-MST probe arrays to fast diagnostic testing of anechoic chambers and microwave antennas”, AMTA '97. 19th Meeting and Symposium, pp. 392–397 (1997).
“On-line control in wood and paper industries by means of rapid microwave linear sensors”, Conference Proceedings, 22nd European Microwave Conference 92 vol. 2, pp. 1037–40 (1992) discloses a measurement using microwave sensors respectively arranged at a plurality of positions by modulated scattering techniques (MST) . Moreover, “Advanced MST probe arrays for rapid diagnostic imaging”, Proc 20th Annu Meet Symp Antenna Meas Tech Assoc 1998, pp. 241–246 (1998) discloses a high-speed diagnostic testing of an antenna in a near-field or a far-field by an electromagnetic wave measuring system using A-MST. In addition, “Optimization of the arrangement compact range-moduled scattering probe array for rapid far-field antenna measurement”, IEE Conf Publ (Indust Electr Eng) No. 370 Pt 1 1993, pp. 376–379 (1993) discloses a measuring method for measuring a far-field pattern of an antenna by the MST which requires no mechanical movement.
“Rapid near-field antenna testing via arrays of modulated scattering probes”, IEEE Trans Antennas Propag Vol. 36 No. 6 1988, pp. 804–814 (1988) discloses a measurement of a near-field of an antenna which uses an array of a number of scattering devices. Also, “Accuracy and speed characteristics of the bistatic MST for rapid near-field antenna measurements”, AP-S Int Symp (IEEE Antennas Propag Soc) Vol. 1987, No. Vol. 1, pp. 174–177 (1987) discloses a method for quickly performing the near-field measurement by using a small scattering probe.
In the conventional electromagnetic wave measuring apparatus, however, a large-scaled mechanism for scanning the large measuring antenna such as the dipole antenna on the circular arc is required. Moreover, since two driving mechanisms, i.e., the scanning mechanism for scanning the measuring antenna and another mechanism for rotating the antenna to be measured are used in the measurement, the measurement takes a long period of time.